U2 star Bono is stunned when critics mock his efforts to wipe out world debt because his humanitarian work is the most rewarding part of his life.

The rocker is baffled by those who feel his efforts are a waste of time, because he has seen huge changes in seven years of urging the world's leading powers to aid struggling nations.

Bono says, "We started this seven years ago. A lot of people worked for this and now 36 of the poorest countries on the planet have had their debts entirely wiped out, not just by the United States but all the rich countries and the World Bank.

"That is an amazing thing. It's the beginning of a new relationship between the haves and the have-nothings.

"We've got to start describing this as an adventure, not a burden... This is a generation, the first generation ever, to have the technology and the resources to actually turn around this extreme poverty trap and I just can't think of a better thing to be doing with my time."